Field of the Invention
This invention relates to a valve and to a closure member of a valve.
Description of Prior Art
Previously there is known a valve having a closure member arranged between an inlet and an outlet of the valve. The closure member is rotatably arranged in the valve such that it may be moved between a closed position and an open position. An inlet surface in the closure member is provided with an inlet opening for receiving a flow, which is passed on via an outlet surface of the closing member. The amount of fluid which can pass through the valve depends on the angle into which the closure member is rotated and on the geometry of the closure member.
A problem with the known solution relates to the pressure difference which is generated between the inlet and outlet side of the valve while the closure member is restricting flow from the inlet to the outlet.
Flow velocity is increased within closure member and outlet because of decreased flow area causing high velocity jet flow. This can lead to noise problems with compressible fluids. High flow velocity will lead to low pressure and with liquid fluids this can lead to cavitation problems. With particles in flow media erosion problems may arise. Flow velocity distribution is dependent on closure member design. At outlet in case of flow separation there are strong vortices which cause low pressures and flow instabilities and may lead to also mechanical vibration accompanied with other aforementioned problems.